Ayanokouji’s Guide to Using Tools at Butei High - Chapter 18

I withdrew my gaze as if nothing had happened.

After all, I had only turned my attention elsewhere to mask an unnatural movement caused by a sudden piercing pain in my ear; I hadn’t expected to lock eyes with Archer by chance.

The so-called ‘eavesdropping devices’ are divided into two types based on their method of transmitting information: traceable and untraceable. I naturally chose the latter; even a top-tier hacker wouldn’t know who the monitoring party was.

I only needed to keep my head down and pretend it had nothing to do with me. Furthermore, I had made extensive preparations—

The working principle of an eavesdropping device is the same as that of a radio station; both utilize the air vibrations caused by human speech, which are converted into audio electronic signals in a sensor, passed through a modulator, exported by a transmitter, and finally picked up by a receiver.

As for controlling the content of the eavesdropping over varying distances, this can be managed using fixed-frequency signals.

Therefore, I only needed to select an applicable device according to my situation.

The device at the Tohsaka residence was made using the principle of laser-measured vibration. That is to say, as long as a sound occurred inside the room, it would cause the glass to vibrate. At that point, the reflected laser beam projected onto the glass would change due to the glass’s vibration.

The characteristic of this type of eavesdropping device is that as long as a home has glass windows, the goal of eavesdropping can be achieved without installing a device inside the room.

Although the principle has existed for fifty years, only the power supply method, the size of the device, and the scope of application have changed. However, I re-adjusted it myself, transforming it into the form of a radio; by tuning it to the corresponding frequency, I could listen to the content of the next monitored location.

What Archer had just crushed was not the one I placed at the Tohsaka house, but the one outside the Church.

I have a habit of scouting locations and making complete preparations before acting, especially when the destination is an unknown territory. Anything that can be associated with magecraft is mostly linked to religion, particularly when there is talk of a Holy Grail involved. I did not come to Fuyuki City prepared to sacrifice my own life and safety.

Counting from now, it was the Night Before.

On the night before, newly arrived, I placed an eavesdropping device outside the Church. I was discovered by a person in a black bodysuit and a white skull mask standing guard outside. He did not act, but instead told his Master—Kotomine Kirei, who was already hiding in the Church—that someone is outside the Church.

The reason I knew this was because I heard everything. Assassin didn’t seem to know what I was doing; he only said someone was lurking near the Church and didn’t touch the device. I sat in the hotel adjusting the frequency myself to monitor the content.

The simplified process was: “Assassin reports to Kotomine Kirei,” “Kotomine Kirei, not wanting the fact of Assassin’s faked death to be exposed, has the Church take over the matter,” and “Kayneth, one of the Masters who had just been provoked by the Tohsaka family using Archer to kill Assassin, wanted to show off his abilities while also doing a favor for the Church, so he proactively sent his Heroic Spirit Lancer to hunt me down.”

The above is what I deduced based on the information I collected over the past two days. Whether the process was more twisted and complex, or exactly as I guessed, doesn’t matter; the result was ‘Lancer coming to hunt me down.’

If Berserker hadn’t come to save me the night before, I naturally had a solution.

The first step—coming to Tohsaka to cooperate—also included the intention of ensuring Assassin’s Master wouldn’t come looking for trouble with me. Tohsaka and Kotomine Kirei are in a teacher-student relationship as well as partners; that play where Archer kills Assassin was also choreographed by them. If Matou and Tohsaka are partners, Kotomine Kirei will temporarily refrain from targeting the partner’s interests.

Whether Matou thinks I am planning solely for him or thinks I have selfish motives, it doesn’t affect our cooperation.

However, a strange variable has appeared now—Archer.

I am not sure if Archer understands what the object he crushed is. After all, according to what I’ve heard, Archer has some personal dealings with Kotomine Kirei; he should also know that I was once hunted by Kotomine Kirei.

While I was thinking, the chair in front of me was pulled back, and the blond youth sat down across from me. He leaned back against the chair, looking at me with a leisurely expression.

The American scientist Franklin once said, “If the disaster has not appeared, our fear is in vain. If the disaster has already appeared, fear will only increase our pain.”

I feel there is no need for me to panic now.

So, I slowly took a sip of tea.

“Do you know what this is?”

Archer placed the scattered parts on the table. He arched an eyebrow at me, looking as if he wanted to see if I would play dumb and refuse to admit what they were.

I said flatly: “Is it not obvious? This is a pocket micro-machine equipped with internet networking equipment developed based on the TCP/IP protocol and Digital Signal Processors (DSPs) capable of performing discrete-time signal processing calculations extremely quickly in a short period, thereby achieving data transmission, compression, amplification, modulation of digital signals, and radio reception.”

Seeing that he didn’t answer, I said: “Do you have any further questions?”